Stroke is the number three killer in the United States, affecting almost 800,000 people each year, according to the National Stroke Association. These "brain attacks" occur when blood flow to the brain is interrupted (an ischemic stroke) or when a blood vessel in the brain leaks or bursts (a hemorrhagic stroke). For 144,000 people each year, the result is death. Hundreds of thousands of others are left with long-term disabilities.

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Genetics, age and race play a role in stroke, as do many other factors, both controllable and uncontrollable. Recent research has teased out more and more of these risk factors, from how you eat to where you live.

Here's what scientists are finding are top risks for a stroke:

7. High-fat diet
The same foods associated with heart attacks — red meat, anything fried — can also raise your risk of a brain attack. At the American Stroke Association's (ASA) International Stroke Conference in February, researchers from the University of North Carolina presented findings that post-menopausal women who consumed high-fat diets had 40 percent more incidences of ischemic stroke than low-fat eaters. Trans fats, found in processed foods like pastries and crackers, seem particularly nasty: The group of women who consumed seven grams of trans fat each day had 30 percent more stroke incidents than those who ate one gram.

So what to eat instead? Multiple studies suggest that a Mediterranean-inspired diet can lower stroke risk. That means lots of vegetables, whole grains, fish, olive oil, nuts and seeds, and very little red meat and sweets.

6. Being single
If you're a man who'd like to cut his chances of a fatal stroke, get hitched. A Tel Aviv University study of more than 10,000 Israeli men found that those who were married at midlife were 64 percent less likely to die of a stroke during the next 34 years than single men. The data was adjusted for other stroke risk factors like socioeconomic status, blood pressure and smoking.

But there's a catch: The marriage has to be a happy one. Men who reported dissatisfying marriages were just as likely as single men to die of a stroke, the researchers reported at the ASA's International Stroke Conference.

5. Being unhappyHappiness is music to your cardiovascular system. Researchers at the University of Texas Medical Branch in Galveston reported in 2001 that among older individuals, positive moods and attitudes protected against strokes. Even incremental increases in happiness helped: For every step up on the researchers' happiness scale, male participants' stroke risk dropped 41 percent. Women's risk dropped 18 percent per happiness unit.

Even if you're not happy, it might pay to act like you are. The researchers speculate that happy peopleare more likely to get medical care, exercise and stay healthy, all protective factors against stroke.

4. Being obese
More weight means a higher risk of stroke, according to researchers from the University of Minnesota. In a study presented at the International Stroke Conference last month, researchers followed more than 13,000 Americans for 19 years and found that the risk of stroke in people with the highest body mass index (BMI) was 1.43 to 2.12 times higher than in those with the lowest body mass index. (BMI is calculated with a person's height and weight and is considered an indicator of body fatness.)

The reason for the correlation is that some stroke risk factors are worsened by obesity, study co-author Hiroshi Yatsuya said in a statement. The biggest culprits, according to the data are high blood pressure and diabetes.

3. Smoking
Lighting up nearly doubles your risk of stroke, according to the American Heart Association (AHA). Fortunately, quitting can drop that risk back down, even for heavy smokers. One 1988 study found that former smokers had the same rate of stroke as nonsmokers five years after snuffing their last cigarette.

2. Being born in the wrong demographic (for a stroke)
Unfortunately, not all risk factors are under your control. Blacks have twice the incidence of strokes as whites, according to the AHA. Not only that, but the death rate from stroke is significantly higher for blacks than the overall stroke death rate. Part of the disparity may be explained by higher-than-average rates of diabetes and high blood pressure among blacks.

Being female can also put you at a disadvantage when it comes to stroke. In a study presented at ASA's International Stroke Conference, University of Southern California researchers reported that women aged 35 to 64 are almost three times as likely to have a stroke as men of the same age. The reason may be that women in midlife carry more abdominal fatthan men, a risk factor for stroke, said the researchers.

1. Being a born-and-bred Southerner
The swath of stroke-prone states across the Southeastern United States — generally including North and South Carolina, Georgia, Tennessee, Arkansas, Mississippi and Alabama — have long been known as the "Stroke Belt." But recent research suggests that just being born and spending your childhood in one of these states raises your risk for stroke, even if you move away later.

In a study published in the journal Neurology in 2009, Harvard public health professor Maria Glymour and her colleagues reported that among blacks, being born in the Stroke Belt increased the risk of stroke by 22 percent. For whites, the number was 30 percent. Part of the reason may be due to risk factors like poor diet, smoking and obesity, which may start earlier in southern states, Glymour told LiveScience.

"By the time that they're middle-aged and we're enrolling them in our studies, it looks like lots of people have those risk factors," she said. "But maybe people in the South have been carrying them for longer."